Sequence diversity of the FT gene in diploid Rosa

To understand the polymorphism of the FLOWERING LOCUS T(FT) homologous gene in Rosa and its relationship between different rose germplasm types, we cloned the FT homologous genes from 73 diploid Rosa germplasms. The sequence polymorphisms of the FT genes were analyzed using multidimensional scaling(MDS) cluster visualization. In total, 215 nucleotide polymorphism loci were detected in 73 diploid materials, including 214 SNPs and one deletion locus, with an average of 185 bases and one mutation. For amino acid polymorphism, a total of 35 amino acid mutations were detected, with an average of 379.6 amino acids and one mutation. Statistical analysis of the mutation sites showed that the 39, 258, and 426 bp sites were high-frequency mutation sites, and the bases were A or C mutated to T. The MDS cluster visualization analysis results indicated that the differences in the base mutations of the FT gene coding region of the three taxa were wild species > Sect. Chinenses DC. > Chinese old garden roses, and the amino acid variance within groups was Chinese old garden roses > Sect. Chinenses DC. > wild species. Thus, we speculated that during the long-term cultivation and domestication of the Chinese old garden rose, the FT genes experienced strong artificial selection pressure. We further identified close genetic similarity among the Sect. Chinenses DC., wild species, and Chinese old garden roses. However, the genetic relationship between wild species and Sect. Chinenses DC. was further apart. This indicates that Sect. Chinenses DC. may be an important parent of the Chinese old garden roses.